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Study on a free electron laser in a THz region using a modulation beam emitted from a micro-field emitter

利用微场发射器发射的调制光束研究太赫兹区域的自由电子激光器

基本信息

批准号：
17206036
负责人：
MIMURA Hidenori
金额：
$ 30.53万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17206036/
关键词：
micro field emitter Smith-Purcell radiation free electron laser GaAs Photocathode metal grating Plused electron beam 電界放射微小電子源テラヘルツ電子ビーム回析格子 Si

项目摘要

1.We observed Smith-Purcell radiation try passing a dc-electron beam emitted from a micro field emitter on an Al grating. The beam current, and acceleration voltage were 200nA and 25-30kV, respectively The pitch of the grating was 416nm. The observed radiations were 4th harmonic one in the ultraviolet region around 350nm, 3rd harmonic one around 400nm, 2nd harmonic one around 600nm, and fundamental one around 1300nm. The wavelength of the observed Smith-Purcell radiation agrees with the smith-Purcell theory.2.To realize a free electron laser, a high frequency electron pulsed beam is necessary. We have developed a fabrication process of a p-type GaAs emitter using a wet etching for the generation of the high frequency pulsed beam. We performed the (NH4)2Sx surface treatment on GaAs a emitter. As the result, we observed a clear saturation of the emission current for the p-type GaAs emitter, because the treatment eliminated the surface oxide, improved the surface roughness, and prevent the oxidation of the surface.3.We also develop a fabrication process of a GaAs photocathode for the generation of the high frequency puked beam. We employed a Yo-Yo method for making a negative electron affinity of the GaAs surface. As the result, we have succeeded in fabricating a GaAs photocathode with a quantum efficiency of 2%.

1.我们用微场致发射器发射的直流电子束在铝栅上进行Smith-Purcell辐射实验。束流为200 nA，加速电压为25- 30 kV，光栅间距为416 nm。在紫外区观测到的辐射为350 nm附近的四次谐波辐射、400 nm附近的三次谐波辐射、600 nm附近的二次谐波辐射和1300 nm附近的基波辐射。观察到的Smith-Purcell辐射波长符合Smith-Purcell理论。2.为了实现自由电子激光，需要高频脉冲电子束。我们发展了一种利用湿法腐蚀产生高频脉冲束的p型GaAs发射极的制造工艺。我们对GaAs发射极进行了（NH_4）_2S_x表面处理。实验结果表明，p型GaAs发射极的发射电流明显饱和，这是因为处理消除了表面氧化层，改善了表面粗糙度，防止了表面氧化。3.我们还开发了一种用于产生高频脉冲束的GaAs光电阴极的制备工艺。我们采用Yo-Yo方法使GaAs表面的电子亲和势为负。结果，我们成功地制作了量子效率为2%的GaAs光电阴极。